University of Isfahan Taxonomy and Biosystematics 3115-9001 15 56 2023 11 22 Thrips associated with Judas trees (Cercis siliquastrum L.) and population fluctuation of Judas thrips, Thrips vulgatissimus Haliday in the Arghavan Strait of Ilam county تریپس‌های مرتبط با درختان ارغوان (Cercis siliquastrum L.) و تغییرات جمعیت تریپس ارغوان، Thrips vulgatissimus Haliday در تنگه ارغوان شهرستان ایلام 65 78 28401 10.22108/tbj.2024.140674.1253 EN Diba Moheby M. A Student in Entomology, Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, Razi University, Kermanshah, Iran Abbas Ali Zamani Associate Professor, Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, Razi University, Kermanshah, Iran Majid Mirab-balou Associate Professor, Department of Plant Pathology, Faculty of Agriculture, Ilam University, Ilam, Iran Behzad Miri PhD student, Department of Plant Pathology, Faculty of Agriculture, Faculty of Agricultural Sciences and Engineering, Kermanshah, Iran Journal Article 2024 02 09 In this research, the fauna of thrips associated with Judas trees (Cercis siliquastrum L.), and the population fluctuation and spatial distribution of Judas thrips (Thrips vulgatissimus Haliday) were studied in the Arghavan Strait located in Ilam city (west of Iran) during the years 2022-2023. In each sampling, 20 trees and four branches of 20 cm on each tree in different geographical directions were selected as the sampling unit. Sampling was done every three days; the branches of Judas trees were shaken on a white plastic tray, and then the thrips were transferred into an Eppendorf tube containing 75% ethyl alcohol. A total of 10 thrips species were collected and identified. The results showed that the Judas thrips have two population peaks. The first population peak was observed on the first day of April 2023. The highest population density was obtained in the first peak with an average of 30.60 ± 6.23 thrips per sampling unit, and the highest density in the second peak with an average of 73.75 ± 7.64 thrips per sampling unit. The results of the spatial distribution based on Taylor’s power law methods showed that the spatial distribution was aggregated. In addition, geographical directions had no significant effect on the density of Judas thrips. Based on the goodness of fit, the Taylor’s power law method was more suitable than Iwao’s patchiness method for estimating the spatial distribution of this species. Key words: Thysanoptera, Judas thrips, flower stage, spring, western Iran. Introduction The Judas tree, Cercis siliquastrum L. (Fabaceae), is a small deciduous tree from Southern Europe and Western Asia, which is noted for its prolific display of deep pink flowers in spring. In Iran, this plant grows in the provinces of Ilam, Kerman, Mazandaran, Guilan, Hamedan, Lorestan, Fars, Kermanshah, and Khorasan-e Razavi. More than 6,400 thrips species belong to the Thysanoptera order, which have been described and recorded. Thrips are widely distributed insects, of which 1% are considered harmful for crops, with the most harmful thrips belonging to the Thripidae family. Up to the present, 12 thrips species have been collected on Judas trees, but all of them also live on other plants. Nine of these thrips were reported from Southern France in three different families: Aeolothripidae (Aeolothrips ericae Bagnall, A. gloriosus Bagnall, A. melaleucus (Haliday)), Melanthripidae (Melanthrips rivnayi Priesner), and Thripidae (Thrips flavus Schrank, T. major Uzel, T. meridionalis Priesner, T. minutissimus L., and T. tabaci Lindeman). Three of these were reported from Iran, all belonging to the Phlaeothripidae family: Haplothrips flavicinctus Karny (from North Khorasan province), H. reueri (Karny), and Neoheegeria persica Priesner (from Fars province). Here, the fauna of thrips associated with Judas trees, and the population fluctuation and spatial distribution of Judas thrips (Thrips vulgatissimus Haliday) were studied in the Arghavan Strait located in Ilam city (west of Iran) during the years 2022-2023. Materials & Methods Thrips specimens were collected every week from flowers of Judas trees in the Arghavan Strait located in Ilam city (west of Iran) from April to the end of May 2023. Flowering branches from different trees were shaken onto a white tray. The fallen thrips were transferred to Eppendorf tubes containing 70% ethyl alcohol. Samples were brought to the laboratory, examined under a stereoscopic microscope, and prepared onto microscopic slides using the method of Mirab-balou and Chen (2010) for further diagnosis. In addition, flowers were randomly collected and checked individually. For population fluctuation, on each Judas tree, four branches were selected and 20 cm of the ends of these branches were shaken on a white plastic tray to separate the thrips. Research finding Faunistic study: A total of 10 thrips species belonging to six genera from four different families were collected and identified from the flowers of the Judas trees located in the Arghavan Strait: Aeolothripidae (Aeolothrips intermedius Bagnall), Melanthripidae (Melanthrips fuscus (Sulzer)), Thripidae (Frankliniella intonsa (Trybom), F. occidentalis (Pergande), Tenothrips frici (Uzel), Thrips meridionalis (Priesner), T. tabaci Lindeman, T. vulgatissimus Haliday), and Phlaeothripidae (Haplothrips leucanthemi (Schrank) and H. reuteri Karny). All the specimens were collected and identified on the flowers of Judas trees. Except for Judas thrips, T. vulgatissimus, which had a very high population on the flowers, the rest of the species were only collected randomly during sampling. Population fluctuation: The results showed that the Judas thrips population has two population peaks. The first population peak was observed on the first day of April 2023. The highest population density of Judas thrips was obtained in the first peak with an average of 30.60 ± 6.23 thrips per sampling unit, and the highest density in the second peak with an average of 73.75 ± 7.64 thrips per sampling unit. The results of the spatial distribution based on Taylor’s power law methods showed that the spatial distribution was aggregated. In addition, geographical directions had no significant effect on the density of Judas thrips. In general, the results of this study showed that the population density of Judas thrips in the first peak was higher than in the second peak. Based on the goodness of fit, the Taylor’s power law method was more suitable than Iwao’s patchiness method for estimating the spatial distribution of this species. Discussion of Results & Conclusion In this study, despite many samplings, a small number of thrips species were collected and identified from Judas trees, so that on most trees (only in the flowering stage), only one species, namely Thrips vulgatissimus Haliday, was dominant. In addition, there were no thrips species on the Judas leaves. Therefore, based on the results of this research, thrips were active only in the flowering stage of Judas trees, and after the flowers fell, their very high population suddenly disappeared. The present study showed that the activity of the Judas thrips in the Arghavan Strait began in the first decade of April. Considering that the Arghavan Strait is also a part of the Zagros forests in Ilam province and a combination of different trees can be seen in Zagros, therefore, based on other studies conducted in the Zagros forests, it indicates the beginning of the activity of different species of thrips is from the beginning of April. Acknowledgment We are grateful to anonymous reviewers for their useful comments. This paper is extracted from part of the MSc thesis of the senior author, who was financially supported by research vice-chancellor of Razi University, Kermanshah, Iran.

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